You know it when you feel it: the effervescent joy that makes you want to kiss strangers, sing an aria, dance in the crosswalk at rush hour. Sometimes these surges of energy are the direct result of external events -- a big promotion, a great workout, a fabulous first date. More often, happiness floods in unexpectedly, and we chalk it up to that mysterious force known as a good mood.

But what if this bubbly, pure sensation isn't completely random? What if you could tap into it, nurture it? India's ancient health system, Ayurveda, says you can, and it has a name for the force that flows through us when all is well: ojas (OH-jas). "Ojas is your energy, your vitality, your immunity, your fertility, your longevity, and your joie de vivre," says medical herbalist and Ayurvedic practitioner Anne McIntyre, author of more than a dozen books on natural health. By cultivating ojas, experts say, you can experience deep, genuine joy more often and attain a new level of vibrant health.

Keep reading so you can start feeling better.